1. Field of the Invention
The present invention relates to a focusing device, a camera system and a focusing method that effect a wobbling operation of a first focus lens group in focus lens groups to bring a subject into focus (autofocus: AF).
2. Description of the Related Art
As a prior art of focusing, a method is known which comprises effecting a wobbling operation (micro-vibration) of a lens in an optical axis direction to detect a focus evaluation value, and detecting a focus deviation direction based on a change in the focus evaluation value at this moment. For example, Jpn. Pat. Appln. KOKAI Publication No. 2005-221798 discloses an autofocus system that includes a wobbling lens group and a focus adjustment lens group and individually moves these lens groups.
In Jpn. Pat. Appln. KOKAI Publication No. 2005-221798 mentioned above, the wobbling lens group is wobbled to detect a focusing direction, the focus adjustment lens group is moved in this detected focusing direction, and then the wobbling lens group is again wobbled to determine whether focusing is achieved. If a result of this determination is non-focusing, the focus adjustment lens is again moved in the focusing direction detected by the wobbling. The above-described operation is repeatedly performed until the focusing is achieved.